Police in Indonesia released CCTV footage today of two suicide bombers checking into the luxury Jakarta hotels that they blew up last Friday.

The co-ordinated blasts at the JW Marriott and the Ritz-Carlton hotels in the city's business district killed nine people, including three Australians, a Dutch couple and a New Zealander. More than 50 people were wounded in the worst terror attacks in Indonesia since 2005.

The latest video shows the Marriott bomber, dressed in a coat and baseball cap, passing easily through the hotel's airport-style security checks with his suitcase.

Footage has already been released on local television showing the same man wearing a backpack on his chest and dragging a suitcase as he headed into the dining area, not long before the explosion.

A security guard is understood to have asked him where he was going. He replied that he was going to give something to his boss.

The bombers are believed to have checked into the Marriott on Wednesday as paying guests and assembled their bombs in their room, number1808 on the 18th floor.

Police say that the attacks appear to have been co-ordinated by Noordin Mohammed Top, the leader of an extreme offshoot of Jemaah Islamiyah, a South East Asian terror network. An unexploded bomb found in a laptop case in the bombers' bedroom at the Marriott was said to be similar to the devices used in the 2002 Bali bombings, and to one found in a recent raid on a Noordin hideout.

Detectives have yet formally to identify the Jakarta attackers, but said today that they were closing in, questioning staff at an Islamic school in Java and taking DNA samples from relatives of suspects in the towns of Temanggung and Cirebon.

Local media have named the Marriott bomber as Nur Jasbi, also known as Nur Said, from Temanggung, Central Java, and the Ritz-Carlton attacker as Ibrahim, originally from Cirebon, West Java, who worked as a florist in the hotel.

A teacher at the Al-Mukmin Islamic school in Ngruki, Central Java, said that a student called Nur Said had graduated in 1994 at the same time as Asmar Latin Sani, a suicide bomber who blew himself up in a truck outside the Jakarta Marriott in 2003.

"He was just like normal students, nothing extraordinary about him. He graduated in 1994 with Asmar," said the teacher, also known as Ibrahim. Several former students at Al-Mukmin have gone on to carry out terror attacks for Jemaah Islamiyah, although Ibrahim denied that it was a training ground for suicide bombers.

Today an office block near the Australian embassy was searched after fresh bomb threats. Security has been stepped up at Pertamina, the state oil and gas firm, after other threats and the Royal Bank of Scotland is among a number of companies to temporarily ban staff from visiting Indonesia, while Citigroup and other banks have placed restrictions on travel.

Today Susilo Bambang Yudhoyono, the Indonesian President, tried to steady confidence, saying that his country could guarantee security.

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